What’s Lurking in the Water – Understanding Blue-Green Algae

Weather and water conditions in many parts of the country have created or will create conditions favorable for the rapid growth of blue-green algae. Please be on alert with your horses, other animals and yourselves, and use precaution around water sources.

These single-celled organisms are actually algae-like bacteria instead of being true algae and are also referred to as Cyanobacteria.  They grow rapidly and may produce the pea-soup green color in some bodies of water, along with some foul odors.  The rapid growth periods, called “blooms” most frequently occur when there is a combination of warm weather, intermittent or limited rainfall and an accumulation of nutrients, particularly phosphorus and nitrogen. Blooms can range in color from green, to blue, brown or red. Water sources of fresh, brackish or salt water can all be affected by harmful algal blooms. Most often, slow moving water sources are the most suspect, although harmful algal blooms can occur in any water source with favorable conditions.

The planktonic groups produce the pea green water while the mat-forming groups produce dark mats that start on the bottom and float to the surface.  The planktonic species (Anabena, Aphanizomenon and Microcystis) are believed to be most likely to produce toxins which can be harmful or fatal to animals when ingested. Although, you cannot tell by looking at the bloom whether or not cyanotoxins exist. (Fact Sheet on Toxic Blue-Green Algae, Purdue University, Carole A. Lembi)

Toxins may be ingested when animals drink the water, when they lick their coats after being in the water, or when they inhale water droplets.  Animals are more likely to consume the water if fresh, clean water supplies are limited from other sources. Not all animals are deterred by foul odors that may be produced from the blooms.  Animals that drink or have exposure to the water during a period when cyanotoxins are being produced may be affected, but toxins are not always produced when there is a bloom.

Providing a source of fresh, clean, safe drinking water is the best way to avoid causing animals to consume questionable water.  If animals go swimming, they should be cleaned off before they have a chance to lick their coats, try not to engage in physical exertion near the water supply where inhaling water droplets could occur.

Preventing access to waterways is one way to prevent toxin exposure. Swimming in, contact with, breathing in water droplets or drinking water in ponds/lakes/streams is not recommended during temperatures or conditions that are favorable for blooms to exist. Most often slow moving water or calm water that has a greenish appearance are those most suspect to algal blooms, however they can exist an any water source if the conditions have been favorable. If contact has occurred watch for symptoms and promptly notify your veterinarian. When in doubt keep your animals and yourselves out of the water. Provide access to fresh, clean water at all times for your animals.

Toxic symptoms may include:

  • Diarrhea
  • Vomiting
  • Rash and skin irritation
  • Difficulty breathing
  • Seizure
  • Death

While not all “blooms” may produce toxins, avoiding exposure to or consumption of suspect water is recommended.  Risks of illness after the blooms are gone are low, however some toxins can still remain in the water once the blooms are gone. More information is available from local and state pollution control sites or extension sites. Health Departments recommend, when in doubt, keep out of the water.

Preventing run-off of nutrients into ponds and lakes is also important to help reduce the risk of these algae blooms.  Keeping vegetation around water sources can help naturally filter. Drought conditions in some areas have also increased the concentration of nutrients in the remaining water in ponds, lakes and streams.

Blue-Green Algae – A Potential Hazard for Horses, Pets and People

drinkingCurrent weather and water conditions in many parts of the country have created conditions favorable for the rapid growth of blue-green algae. Please be on alert with your horses and dogs, and use precaution when around unfamiliar water sources.

These primative organisms are actually algae-like bacteria instead of being true algae and are also referred to as Cyanobacteria.  They grow rapidly and may produce the pea-soup green color in some bodies of water, along with some foul odors.  These rapid growth periods, called “blooms” most frequently occur when there is a combination of warm weather, intermittent or limited rainfall and an accumulation of nutrients, particularly phosphorus and nitrogen.

The planktonic groups produce the pea green water while the mat-forming groups produce dark mats that start on the bottom and float to the surface.  The planktonic species (Anabena, Aphanizomenon and Microcystis) are believed to be most likely to produce toxins which can be harmful or fatal to animals when ingested. (Fact Sheet on Toxic Blue-Green Algae, Purdue University, Carole A. Lembi)

These toxins may be ingested when animals drink the water or when they lick their coats after being in the water.  Animals are more likely to consume the water if fresh water supplies are limited from other sources.  Any animals that drink the water during a period when toxins are being produced may be affected, but toxins are not always produced when there is a bloom.

Providing a source of fresh, clean, safe drinking water is the best way to avoid causing animals to consume questionable water.  If pets go swimming, they should be cleaned off before they have a chance to lick their coats.

Toxic symptoms may include:

  • Vomiting
  • Diarrhea
  • Rash and skin irritation

Preventing run-off of nutrients into ponds and lakes is also important to help reduce the risk of these algae blooms.  Prolonged drought conditions in some areas have also increased the concentration of nutrients in the remaining water in ponds and lakes.

While not all “blooms” may produce toxins, avoiding exposure to or consumption of suspect water is recommended.  More information is available from local and state pollution control sites or extension sites.   A recent case in Minnesota reported that 2 pets had been killed and a boy was sent to the hospital (MPLS Star Tribune, July 4, 2015, Liz Sawyer) due to exposure to blue-green algae.

Warm Temps & Water Consumption

The transition in temperature and humidity from cool season to warm season may require an adjustment in watering horses. Reduced water consumption may impair performance and may increase the risk of impaction colic. Also, horses that are not conditioned properly may sweat more profusely than a well-conditioned horse, and thus dehydrate faster. This is particularly important early in the season when temperatures may change suddenly and horses may not yet be in peak condition.

The first key element is to make certain that horses have ready access to clean, palatable, cool water at all times or at very frequent intervals. Horses will normally consume about 1 gallon of water per 100 lbs body weight, so an 1100 lb horse will require a minimum of 11 gallons of water per day. This quantity can increase substantially during periods of exercise, high heat/humidity or for lactating mares.

Some tips to keep in mind to keep water consumption up:

  • Horses do not like to consume warm water in warm temperatures. Automatic waterers or large tanks, located in the shade and cleaned regularly, may be good options. If water is supplied in buckets, they need to be cleaned regularly and re-filled regularly.
  • If you are traveling to a show or other competition, it is essential to monitor water consumption, particularly if temperature conditions change.
  • It is routine in many barns to flavor the water with something like wintergreen or peppermint at home so that you can flavor the water in new facilities to match the home water.  Read here for tips on training your horse to drink water away from home.
  • Do NOT use soft drinks or any material containing caffeine as these can trigger positive drug tests.
  • Taking horses to facilities with chlorinated water can sometimes reduce water consumption without proper precautions.

The second key element is to make certain that salt is offered free choice. Things to keep in mind for salt consumption in horses include:

  • Horses require 1-2 ounces of salt per day, and this can increase to 6 ounces per day with exercise in hot weather conditions.
  • Loose salt is consumed more readily than salt blocks in many cases.
  • When evaluating the total diet for salt consumption, commercial feeds normally contain 0.5-1.0% salt. It is not typically any higher than this, due to problems with palatability.
  • If a horse has been salt deficient or is bored, they may over-consume salt while in a stall.
  • Additional electrolytes, commercial or personal recipe, may be used per directions before, during and following completion, but care must be taken to ensure that the horses are drinking adequate water. Administering electrolytes to a horse that is not drinking properly, or allowing a horse to over consume salt without adequate water, can lead to electrolyte imbalances. If electrolytes are added to the water, plain water should be offered also.

Horses need to be offered water throughout the day at a competition, and should be re-hydrated following exertion. They cannot cool out and recover properly without being re-hydrated. Keeping horses properly hydrated and maintaining electrolyte balance is extremely important in order to make a safe transition from cool temperatures to summer time and competition.